Problem when creating additional lines for variants

I just saw that for the standard Italian 500 Lire coin
https://en.numista.com/catalogue/pieces302.html
there are now variants for 1982 small and large head. As well as for the year 1992.
My 1982 coins are listed as small heads, while I only know large heads from 1982-1991 and small heads from 1991 on.
Could it be that at the time when this was split, the existing line was changed to "small head" and a new line "large head" was added? Most of the swap coins are "small heads", only some have "large heads", probably those who added their coins after the split(?)

Or is there a rarer variant with extra large head, called "large head", and the standard head at the size of the 1991 large head is called "small head"?

Anyway, always when new year splits are made, how are we addressing the problem that some (up to half, in cases going wrong most) of our coins are entered in the wrong line?

My idea is that in such cases all entered coins should get a comment [entered before variant split], so the user can see which of his coins have to be examined again to fit the new distinctions. And the swapper will see that the coins he selects from his partner are probably not the exact variant that they are entered as.